Tinnitus – incessant ringing in the ears – can be eliminated by “retuning” part of the brain, scientists have discovered.
The research offers new hope to thousands of people who are plagued by the currently incurable problem.
Researchers were able to halt tinnitus in laboratory rats using a technique that involved nerve stimulation paired with sounds.
An early clinical trial testing the treatment on human patients is due to begin in the next few months.
Tinnitus is often triggered by exposure to loud noise, which destroys cells in the inner ear that transmit sound signals to the brain. Other causes include injury and normal ageing.
Scientists believe the brain tries to compensate for the missing signals, leading to phantom sounds ranging from rattles to roaring, whooshing, or a jet-engine whine. While some people are only mildly affected, others find the noises highly distressing.
One in 10 adults in the UK experiences permanent tinnitus and around 600,000 have it badly enough to affect their quality of life.
The US researchers, whose findings were reported in the journal Nature, carried out experiments on tinnitus-affected rats aimed at inducing changes in the auditory cortex, the part of the brain that responds to sound. By electrically stimulating the vagus nerve – a large nerve running from the head and neck to the abdomen – at the same time as playing sounds tuned to specific frequencies, they banished tinnitus from the rats.
Study leader Dr Michael Kilgard, from the University of Texas at Dallas, said: “When we paired tones with brief pulses of vagus nerve stimulation, we eliminated the physiological and behavioural symptoms of tinnitus in noise-exposed rats.
“The key is that, unlike previous treatments, we’re not masking tinnitus, we’re not hiding the tinnitus. We are returning the brain from a state where it generates tinnitus to a state that does not generate tinnitus. We are eliminating the source of the tinnitus.”
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